Writing a Utility Function | Dataford Interview Questions

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The Teachable Creator Dashboard receives nested configuration objects, and frontend code often needs to safely read a deeply nested value. Implement a Python equivalent of Lodash's get function.

Given a nested object, a property path, and an optional default value, return the value at that path. The path may be a dot-separated string such as user.profile.name, a bracket-index string such as courses[0].title, or a list of path segments such as ["courses", 0, "title"]. Return the default value only when the path cannot be fully resolved.

For this problem, string paths use non-empty property names and non-negative integer list indexes. Bracket notation does not contain quoted property names.

Formal Specification

Implement lodash_get(obj, path, default_value). obj is a nested combination of dictionaries, lists, strings, numbers, booleans, and None. path is either a string or a list containing strings and integers. Return the resolved value, or default_value if any segment is missing or invalid. A resolved None value is valid and must not be replaced by the default.

Constraints

0 <= number of path segments <= 100
Nested objects contain at most 10^4 total values
List indexes are non-negative integers
A missing path and a resolved None must be distinguished
String paths use dot notation and unquoted bracket notation such as items[0].name

Function Signature

def lodash_get(obj, path, default_value):